An electrophotographic laser printer is configured such that a process cartridge including a photosensitive drum and a developing cartridge is detachably mounted in an apparatus body.
There has been proposed a process cartridge, a coupling member, to which a drive force for rotating a photosensitive drum is input, is provided at an end of a photosensitive drum which is rotatably held by a frame body.
In this process cartridge, the coupling member is provided so as to protrude outward from the frame body. When the process cartridge is mounted in an apparatus body of an image forming apparatus, a drive input shaft provided in the apparatus body is fitted to the coupling member. Accordingly, a drive force is transmitted to the coupling member, so that the photosensitive drum is rotated.
However, in this structure, the coupling member protrudes outward from the frame body. Accordingly, when the process cartridge is mounted in or detached from the apparatus body of the image forming apparatus, the coupling member could collide with other members provided in the apparatus body. Therefore, the process cartridge could not be smoothly mounted in the apparatus body. Further, if the coupling member repeatedly collides with other members provided in the apparatus body, there is a concern that the coupling member or other members provided in the apparatus body could be damaged.